BRANDON — On the flat top of this two-story brick building, even nearby trees don't cast a shadow. It's a feature David Ewing hopes will give him a tiny edge in the slowly recovering office-space market.

This week, contractors installed 256 solar panels — row after row of glinting polycrystal, facing south. In time, Ewing would like to see 480 more. They would generate more than half the electricity for the 66,000-square-foot office building with tenants like a medical lab, oral surgeon and travel and real estate companies.

Each month, he figures, the solar boost will cover the cost of privately financing the more than $300,000 project. And he'll have another way to market space in a building that's only about 70 percent full. The solar array could attract companies or government agencies that want to limit their environmental footprint.

"It's a feel-good thing," he said. "We can hopefully fill up our empty space faster than someone who doesn't have that."

The project, perhaps the largest private solar installation in Hillsborough County, is a sign that falling prices and rising incentives will start to attract businesses with an eye on the bottom line.

For decades, the solar industry in Florida focused on pools or hot water heaters. Solar electricity was simply too expensive to be widely attractive.

"Now we're starting to see it shifting from pool heating," said Bruce Kershner, executive director of the Florida Solar Energy Industries Association near Orlando.

It began in 2006, he said, when the Florida Legislature started a solar rebate program that expired in June. Now federal programs are a bigger help. Meanwhile, utility companies will start rolling out details in the new year on their own incentives, he said.

For commercial property, it's just the beginning, said Juniper Duffin, a senior property manager in Clearwater with Colliers International.

So far, most of the focus on energy efficiency has been on low- or no-cost strategies to reduce environmental impact, not expensive shifts to alternative energy, she said. Some building owners have installed solar panels and seen cost-benefit savings, she said, but only over a long time frame.

"One day that'll be one of those things that more building owners will start to buy into," she said. "It takes buy-in from not just the tenants and the owners, but also the leasing agents — everybody who touches that property."

The government's helping to lead the way, she said. Not just with incentives, but with government leases that require energy efficiency, which could favor a building such as Ewing's with a large solar array.

"It's really great to see, because obviously the government has to be on board to make everybody else realize how important it is," Duffin said.

Ewing knows he's making his property more attractive for prospective government tenants. He's also looking forward to a federal check within 60 days for a third of the cost of the system. He figures it's a great time to invest, not just because of incentives, but also because of a lower price tag on construction.

Dean Greene of Solar Specialist Inc. in Brandon worked with Ewing to get installation costs down to $5.25 a watt for the 60-kilowatt system.

"You're going to get more for your money right now," Greene said.

Business has never been better for solar panel installations, he said. Two years ago, three guys could handle the work. This week, a crew of 12 worked on Ewing's roof.

"Every day I think it can't get busier, it does," he said.

Ewing tells him as prices drop, he'll give him more business — when the bill hits $4 a watt, that's when he'll add the extra 480 panels.

Becky Bowers can be reached at bbowers@sptimes.com or (727) 893-8859. Follow her on Twitter at twitter.com/bbowerstimes.

>>Fast facts

Keeping up with incentives

Property owners may benefit from solar tax credit and grant programs — from governments and from utility companies. A few organizations to help you keep track: